Cersei, Hallyne the Pyromancer, Tyrion, Bronn, and possibly Jaime know about the barrels of wildfire secretly hidden underneath Kings Landing. So, if they did not share the secret, then no one else but them know about the wildfire that is scattered underneath the city. read more
“Aerys saw traitors everywhere, so he had his pyromancer place caches of Wildfire all over the city. Beneath the Sept of Baelor and the slums of Flea Bottom. Under houses, stables, taverns, even beneath the Red Keep itself.” So yes, there’s still wildfire in King’s Landing. read more